The present invention relates generally to a vapor control system, and more particularly relates to a vapor control system designed to minimize the escape of benzene vapors into the atmosphere during the loading of liquid benzene into a tank truck. Recently enacted Environmental Protection Agency regulations governing loading of volatile substances into tank trucks specify that a vapor control system is required for substances which have a vapor pressure exceeding 1.5 psia at loading temperature and wherein the loaded volume exceeds 20,000 gallons per day. The present invention was designed to comply with EPA standards during the loading of benzene into tank trucks.